Anti-gun movement seeking new angle?
At Snowflakes in Hell, Sebastian has a thought about the antigun group's apparent increase in references to suicide rather than homicide. He suggests they're angling for recruits among the families of suicides. It's unlikely that they are aiming to find a winning argument for the general population; suicide is the ultimate in "if he can't get a gun, he'll use something else" situation.
He has, I think, a good point. When impacted by a tragedy like that, a person often has a drive to feel that they are doing something about it, thus striking back at the tragedy itself. (That's why Pete Shields essentially founded what is today the Brady Campaign -- before his time it was a tiny group, but as a former Dupont VP he had the skill to make it a big one. His son was murdered by the Zebra Killers, and he was off to do something).
With suicide right now, those impacted can volunteer for suicide hotlines, join local suicide prevention groups with their educational campaigns... in short, do things which are productive but seem small scale. They might be likely recruits for campaigns that can claim a broad national agenda in exchange for donations and volunteers. Add to that the factor that families of the average suicide victim are probably better off financially, and better able to donate, than families of the average murder victim (esp. now that gang killings have become a large picture of that), and that there are more of them.